When designing a new osteosynthesis device, the biomechanical competence must be evaluated with respect to the acting loads. In a previous study, the loads on the proximal phalanx during rehabilitation exercises were calculated. This study aimed to assess the safety of a novel customizable osteosynthesis device compared to those loads to determine when failure would occur. Forty proximal phalanges were dissected from skeletally mature female sheep and divided into four testing groups. A custom 3D printed cutting and drilling guide was used to create a reduced osteotomy and pilot holes to insert four 1.5 mm cortical screws. A novel light-curable polymer composite was used to fixate the bones with an in situ fixation patch. The constructs were tested in cyclic four-point bending in a bioreactor with ringer solution at 37°C with a valley load of 2 N. Four groups (N = 10) had increasing peak loads based on varying safety factors relative to the physiological loading (G1:100x, G2:150x, G3:175x, G4:250x). Each specimen was tested for 12,600 cycles (6 weeks of rehabilitation) or until failure occurred. After the test the thickness of the patch was measured with digital calipers and data analysis was performed in Python and R.Introduction
Method
Traumatic disruption of the pelvic ring has a high risk of mortality. These injuries are predominantly due to high-energy, blunt trauma and severe associated injuries are prevalent, increasing management complexity. This population-based study investigated predictors of mortality following severe pelvic ring fractures managed in an organised trauma system. Cases aged greater than 15 years from 1st July 2001 to 30th June 2008 were extracted from the population-based state-wide Victorian State Trauma Registry for analysis. Patient demographic, pre-hospital and admission characteristics were considered as potential predictors of mortality. Multivariate logistic regression was used to identify predictors of mortality with adjusted odds ratios (AOR) and 95% confidence intervals (CI) calculated. There were 348 cases over the 8-year period. The mortality rate was 19%. Patients aged greater than 65 years were at higher odds of mortality (AOR 7.6, 95% CI: 2.8, 20.4) than patients aged 15–34 years. Patients hypotensive at the scene (AOR 5.5, 95% CI: 2.3, 13.2), and on arrival at the definitive hospital of care (AOR 3.7, 955 CI: 1.7, 8.0), were more likely to die than patients without hypotension. The presence of a severe chest injury was associated with an increased odds of mortality (AOR 2.8, 95% CI: 1.3, 6.1), while patients injured in intentional events were also more likely to die than patients involved in unintentional events (AOR 4.9, 95% CI: 1.6, 15.6). There was no association between the hospital of definitive management and mortality after adjustment for other variables, despite differences in the protocols for managing these patients at the major trauma services (Level 1 trauma centres). The findings highlight the importance of the need for effective control of haemodynamic instability for reducing the risk of mortality. As most patients survive these injuries, further research should focus on long term morbidity and the impact of different treatment approaches.
The aim of this study was to determine predictors of persisting moderate/severe pain post orthopaedic injury. Data were obtained from patients presenting to the two adult level 1 trauma centres in Victoria, Australia between August 2003 and August 2004. The maximum self reported pain levels at discharge and at 6 months post injury were determined using 11-point visual analogue scales (VAS). Moderate/severe pain was defined as a VAS score of 5 or greater. Associations between categorical variables were determined using chi-square tests and adjusted using multivariate logistic regression to determine possible predictors of persistent pain. Data were obtained from 742 patients (age 15–100 years, 60.7% male). 37.1% had moderate/severe pain 6 months post injury. Moderate/severe pain at discharge was associated with an increased risk (OR 2.46 (95%CI 1.72–3.52), p<
0.0001) and isolated upper extremity injuries were associated with a reduced risk (OR 0.43 (95%CI 0.24–0.75), p=0.003) of moderate/severe pain 6 months post injury. Age (p=0.98), gender (p=0.37) and the presence of multiple orthopaedic (p=0.76) or non-orthopaedic injuries (p=0.58) were not predictors of moderate/severe pain 6 months post injury. The severity of pain at discharge was the main predictor of moderate/severe pain 6 months following orthopaedic trauma. Further studies are needed to determine if improving pain control prior to discharge can reduce the incidence of persistent pain following orthopaedic injury.
